In terms of reputation and popularity, the Apple iPhone is still the king of the smartphone market in the United States. But the newest Research in Motion BlackBerry and Motorola Droid models are giving Apple a run for its money.

Everybody loves their smartphone, but no device is perfect -- just ask iPhone owners how they feel about relying on AT&T as their carrier. But what if you could take the best parts of every smartphone currently on the market and combine them to make the world's greatest mobile device? What would you choose? In this slideshow, we give our take on what this Frankenphone would look like by incorporating the best hardware, operating system and enterprise features.

The Motorola Droid certainly hasn't been an "iPhone killer," but it has become a solid alternative to the iPhone for Verizon customers who don't want to switch their carriers. But like every big new smartphone to hit the market, the Droid was far from perfect. With Motorola planning to drop a Droid sequel on the market later this month, we thought it would be a good time to go over the areas we hope the newest version of the device will improve upon the old one.

Whenever a hot new smartphone hits the market, one of the key specifications techies look at is its processor, which is primarily responsible for running the device's main computing functions and applications. But over the past few years, many processor chips have moved far beyond the traditional functions of plain old central processing units (CPU) and are now responsible for an array of functions including power saving, system memory and video processing.

The consensus forming on HTC's EVO 4G seems to be similar to that of Hardee's 1,400-calorie Monster Thickburger: It's terrific, but not for the faint of heart. Everything about the EVO 4G seems to be designed as a super-sized smartphone. Its physical size is striking, with a 4.3-inch 800 by 400 pixel display screen and a weight of 6 ounces.

Android has officially hit the big time now that sales of its devices exceeded the Apple iPhone over the past quarter. Learn more with the Cisco CleanAir Technology Overview: Download nowAndroid's rise is fairly remarkable for an operating system that only just launched in the fall of 2007. The open-source operating system's success is even more impressive when you consider that when it debuted it was already facing a crowded field of OS heavyweights such as the iPhone, BlackBerry, Windows Mobile and Symbian.

Microsoft is on track to launch the completely reengineered Windows Phone 7 platform later this year and seek to recapture some of the exploding smartphone market. However, in the wake of the abysmal failure of the Kin, and following on the heels of the launch of the iPhone 4 and awesome Android handsets like the EVO 4G and Droid X, Microsoft may want to reconsider whether this is even a battle worth fighting.

Smartphones and their apps are the new way of the world, and developers are lured by their increasing popularity. But with two major platforms -- Apple's recently upgraded and renamed iOS 4 and Google's Android -- competing with one another, how does a developer choose between them?

The iPhone 4 is slim and svelte, with a premium feel and a stainless-steel edge. In comparison, the iPhone 3GS looks and feels plasticky. The border of the iPhone 4 doubles as the device's cellular and wireless antennas.

Although phones featuring Google's open source Android operating system have been out for more than a year, it's only been in recent months that the platform has really caught on. In fact, last fall alone saw the debut of several high-profile Android devices from such manufacturers as HTC, Motorola, Sony Ericsson and Samsung. However, all these big smartphone releases are bound to leave casual observers confused -- after all, if so many devices featuring Android are being released at once, how can we differentiate between them? In this slideshow, we'll give you the basic lowdown of each smartphone and break them down by price, carrier, processing speed and other features.